The date of issue for these stamps were 22 July 1981. If you look at the CDS, the '1' from the year has been left out.
Stamps: Prince Charles and Lady Diana Spencer, issued 22 July 1981.
Circular Date Stamp: Field Post Office 1004, 22 JY 8.

The date of issue for these stamps were 9 March 1983. If you look at the CDS, the '1983’ from the year has been left out.
Stamps: Commonwealth day, Geographical Regions, issued 9 March 1983.
Circular Date Stamp: Field Post Office1019, 9 MR.

Stamps: Royal Wedding, issued 22 July 1981.
Special Handstamp: BFPS 1753, The Royal Wedding of the Prince of Wales and Lady Diana Spencer, 29 July 1981.
Note: Not an official First Day Cover but a commemorative cover of the The Royal Wedding.